1) The commutator should have a positive cylindrical surface, and there should be no signs of mechanical damage or scorching.
(2) After the commutator runs without sparks for a long time under load, a hard film with brown luster will be formed on the surface. This is a normal phenomenon. It can protect the commutator from wear and tear. This film must be protected and cannot be used Emery cloth friction.
(3) If the surface of the commutator is rough, scorched, etc., use "0" emery cloth for fine grinding on the surface of the rotating commutator. If the surface of the commutator is too rough, uneven, out of round or partially recessed, the commutator should be turned. The turning speed should not exceed 1.5m/s, and the turning depth and the amount of feed per revolution should not exceed 0.1mm. The commutator should not move axially during turning.
(4) When the surface of the commutator is worn a lot, or after turning, the mica sheet is found to protrude, and the mica sheet should be milled into a groove of 1~1.5mm with a milling cutter.
(5) When turning the commutator or engraving the mica sheet, it is necessary to prevent copper shavings and dust from intruding into the armature. Because the end of the armature coil and the joint piece should be covered. Clean with compressed air after processing.
